Magnetic calipering device



Dec. 21, 1954 WATSON MAGNETIC CALIPERING DEVICE Original Filed April 3,1950 MAGNET N MW E W 5 F @m m 1? M 58 United States Patent MAGNETICCALIPERING DEVICE George F. Watson, Racine, Wis., assignor to TheChristensen Machine Company, Racine, Wis., a corporation of WisconsinOriginal application April 3, 1950, Serial No. 153,520,

now Patent No. 2,637,115, dated May 5, 1953. Divided and thisapplication July 29, 1952, Serial No. 301,583

12 Claims. (Cl. 33-143) This invention relates to calipers and refersmore particularly to magnetic calipering devices designed to detect anabnormal condition capable of causing movement of a feeler, as forinstance, an insufficient thickness of sheet material being fed to amachine.

This application is a division of my copending application Serial No.153,520, filed April 3, 1950, now Patent No. 2,637,115 for MagneticCalipering Device.

It is recognized that the broad concept of utilizing a magnet inconnection with a sheet caliper or excess thickness detector is old.However, as far as known, magnets have not been used in the past totrigger a relatively strong force capable of producing a considerablymagnified motion upon detection of a decrease in the thickness of sheetmaterial being ealipered, or upon the absence of a sheet at a time whenand at a place where a sheet should norznally be present.

The purpose of this invention thus is to provide a sheet caliper orcalipering device wherein the magnetic force of a magnet couple normallyoverpowers the force normally overpowers the force of a spring or othermotion producing device to restrain the same and thereby preventactuation of the mechanism which is operated by the spring or othermotion producing device as long as a predetermined normal conditionexists under a feeler, but to effect release of the force of the springor other motion producing device upon a reduction in the magnetic forcebrought about by a separation of the elements of the magnet coupleresulting from a decrease in the thickness of a sheet being calipered,or the absence of a sheet in calipering position.

Hence, it is possible with this invention to not only magnify the slightmotion produced by response of a feeler to an abnormal condition to bedetected, but to also release a strong force with a snap action.

With the above and other objects in view, which will appear as thedescription proceeds, this invention resides in the novel. construction,combination and arrangement of parts substantially as hereinafterdescribed and more particularly defined by the appended claims, it beingunderstood that such changes in the precise embodiment of thehereindisclosed invention may be made as come within the scope of theclaims.

The accompanying drawing illustrates one example of the physicalembodiment of the invention constructed according to the best mode sofar devised for the practical application of the principles thereof, andin which:

Figure l is a side view of a sheet calipering device embodying theprinciples of this invention; and

Figure 2 is a view similar to Figure 1 but showing the mechanism trippedin response to a decrease in the thickness of the material beingcalipered.

Referring now to the drawings, there is shown, by way of example, oneform of sheet calipering device constructed and operated in accordancewith the present invention, which is well adapted for use on signaturegathering machines designed to feed individual signatures and groups ofsignatures to a signature stitching machine, as well as on sheet feedingmachines designed to feed sheets in lapped relation or singly one afteranother in spaced relation to printing presses and the like, saidcalipering device acting to trip control instrumentalities of said1nachines upon the detection of a decrease in the thickness of asignature or group of signatures, or of a stream of underlapped sheets,and upon the absence of. a signature. or sheet at calipering positionwhen one should be present.

2,697,281 Patented Dec. 21, 1954 As herein shown, the sheet caliperingdevice comprises cooperating lower and upper feeler rollers 5 and 6,respectively, between which the above mentioned sheet material isadvanced by a suitable conveyor (not shown) forming part of the machineupon which the calipering device is used and with which said device isassociated. The lower feeler roller 5 is mounted for rotation about afixed axis. The upper feeler roller 6 is journalled on a mediallypivoted lever 7 which rocks upon its fulcrum 8 in response to changes inthe thickness of the sheet material passing between and engaged by therollers 5 and 6. The fulcrum 8 about which the lever 7 rocks is carriedby a bracket 9 which constitutes a fixed part of the mechanism, or atleast in operation is fixed with respect to the axis of the feelerroller 5.

The bracket 9 provides an anchor 10 for an adjustable spring stop 11against which a spring 12 reacts to urge the lever 7 counter-clockwiseabout its fulcrum 8. The force of the spring 12 is opposed by themagnetic attraction between the elements of a magnet couple whichconsists of a permanent magnet 13 fixed to the bracket 9 and an armatureelement 14 which is fixed to the outer end of a second lever 15. Thislever 15 is arranged to swing about the fulcrum 8, and a unidirectionaldriving connection is established between the two levers 7 and 15 by anabutment 16 on the lever 7 bearing against the underside of the lever15. Thus, the magnetic attraction between the elements 13, 14 of themagnet couple tends to separate the feeler rollers 5 and 6 in oppositionto the spring 12. in operation, the tension of the spring 12 is adjustedso that it is sufiicient to move the upper feeler roller 6 toward thelower feeler roller 5 against the magnetic attraction of the magnetcouple 13, 14.

Upon detection of a decrease in the thickness of the sheet materialpassing between the feeler rollers 5 and 6, as for instance where lessthan a predetermined number of sheets in a signature or in a stream oflapped sheets is detected, the resulting slight rocking movement of thelever '7 in a counter-clockwise direction about its fulcrum 8 by thespring 12 separates the elements 13, 14 of the magnet couple beyond thecritical spacing for which the device is set, whereupon the magneticattraction between the elements of the magnet couple is reduced andanother spring 17 acting only upon the lever 15 overpowers the magnetand snaps the lever 15 upwardly against a fixed stop 18. This snapmovement of the lever 15, which is considerably greater than the slightmovement imparted to the feeler roller 6 as a result of the detection ofa decrease in the thickness of the sheet material, may be utilized toactuate any desired control instrumentalities, and in the illustratedembodiment rocks a control lever 19 fixed to a rock shaft 20.

When the signatures or sheets are advanced between the feeler rollers 5and 6 in substantially edge-to-edge relation, the feeler roller 6 willride off a preceding signature or sheet and onto a succeeding one, andany decrease in the thickness of a signature or sheet, or break in theprocession of the signatures or sheets due to the absence of a signatureor sheet, will result in actuation of the con trol lever 19, ashereinbefore described. When a stream of lapped sheets of apredetermined number is advanced between the feeler rollers 5 and 6, adecrease in the thickness of said stream due to the failure of the sheetfeeder to feed a sheet and the absence of said sheet in the stream, willlikewise result in actuation of the control lever 19.

A manually movable inhibitor or lock-out stop 21 is provided to lock themovable feeler roller 6 against spring produced downward movement whensaid stop is moved into operative position over a shoulder 22 on thelever 7. Such locking of the feeler roller 6 inactivates the mechanismand is desirable during periods when the machine upon which the deviceis used is being prepared for a produ on r n.

The lock-out stop 21 may be mechanically operated in timed relation withthe passage of the sheet material between the feeler rollers 5 and 6 ina manner well understood in the art. This timing of the operation of themovable feeler roller 6 is desirable when the sheet material is advancedbetween the feeler rollers 5 and 6 in timed relation and spaced from oneanother, and when a stream of lapped sheets is acted upon.

From the foregoing description taken in connection with the accompanyingdrawing it will be readily apparent to those skilled in this art thatthe present invention provides a sheet calipering device which possessesmany advantages over sheet calipering devices heretofore available.

What is claimed is:

1. In a magnetic caliper of the character described, a pair ofcooperating feeler members between which material to be calipered ispassed, said feeler members directly engaging opposite faces of saidmaterial, and one of said members being movable toward and away from theother, support means for said feeler members, biasing means operablyconnected with the movable feeler member for continuously urging thesame toward the other feeler member, a magnet couple comprising amagnetized element and an armature element magnetically attracted towardone another, one of said elements being fixed and the other of saidelements being operably connected with the movable feeler member and sopositioned with respect to the fixed element that the magneticattraction between said elements tends to move the movable feeler memberin a direction away from the other feeler member, said biasing meanshaving a strength suificient to move the movable feeler member inopposition to the magnetic attraction of the magnet couple, and actingto move the movable element of the magnet couple through the movablefeeler member an initial distance away from the fixed element so as toreduce the effective force of magnetic attraction of the magnet coupleupon movement of the movable feeler member toward the other feelermember beyond a predetermined position with respect to said other feelermember, and other biasing means operably connected with the movableelement of the magnet couple for continuously urging said element awayfrom the fixed element, said other biasing means having the strengththereof increased by the magnetic attraction of the movable elementtoward the fixed element and being normally constrained by the force ofmagnetic attraction of the magnet couple from moving the movable elementaway from the fixed element, movement of the movable element by themovable feeler member said initial distance rendering said other biasingmeans effective to overpower the reduced force of magnetic attraction ofthe magnet couple and impart an additional movement to the movableelement away from the fixed element.

2. Apparatus as defined in claim 1, comprising control means responsiveto the additional movement of the movable element of the magnet coupleaway from the fixed element.

3. Apparatus as defined in claim 1 wherein the feeler members eachcomprises a roller.

4. Apparatus as defined in claim 1 wherein the magnetized element isfixed and the armature element is movable.

5. Apparatus as defined in claim 1 wherein the magnetized elementcomprises a permanent magnet.

6. Apparatus as defined in claim 1 wherein the firstand second-namedbiasing means each comprises a spring.

7. Apparatus as defined in claim 1, comprising operable means forreleasably locking the movable feeler member against movement toward theother feeler member by the biasin means connected therewith.

8. In a magnetic caliper of the character described, a magnet couplecomprising a magnetized element and an armature element magneticallyattracted toward one another, one of said elements being movable towardand away from the other, support means for said elements, a springoperably connected with the movable element for continuously urging saidmovable element in a direction to separate the elements of the magnetcouple, said e ements being held by the force of magnetic-attractionagainst spring produced separation as long as the spacin between thesame is less than a critical distance at which the spring overpowers theforce of magnetic attraction, a pair of cooperating feeler membersbetween which material to be calipered is. passed, said feeler membersdirectly en aging opposite faces of said material, and one of saidfeeler members being movable toward and away from the other feelermember, support means for said feeler members, means operably connectingthe movable feeler member with the movable element of the magnet couple,a spring operably connected with the movable feeler member forContinuously urging the same toward the other feeler member, saidlast-named spring having a force sufficient to oppose the magneticattraction of the magnet couple and to efiect movement of the movableelement of said magnet couple at least said critical distance uponmovement of the movable feeler member toward the other feeler memberbeyond a predetermined position with respect to said other feelermember, movement of the movable element said critical distance resultingin a reduction of the force of magnetic attraction of the magnet couplesufiiciently to enable the first-named spring to operate and efiectfurther separation of the elements of the magnet couple thereby, andcontrol means actuated in response to said further separation of theelements of the magnet couple,

9. Apparatus as defined in claim 8, comprising operable means forreleasably locking the movable feeler member against movement by thesecond-named spring toward the other feeler member.

10. In a magnetic caliper of the character described, a pair ofcooperating feeler rollers between which material to be calipered ispassed, said feeler rollers directly engaging opposite faces of saidmaterial, and one of said feeler rollers being mounted in a fixedposition, a pivoted lever mounting the other of said feeler rollers, asecond lever mounted for pivotal movement about the axis of saidfirst-named lever, an abutment on one of said levers and engaging theother of said levers, a magnet couple comprising a magnetized elementand an armature element magnetically attracted toward one another, oneof said elements being mounted on said second lever and the other ofsaid elements being mounted in a fixed position, said elements being soarranged that the magnetic attraction between the same tends to move thefirst-named lever and the feeler roller thereon away from the fixedfeeler roller, a spring operably connected with said second lever forcontinuously urging the same in a direction to separate the elements ofthe magnet couple, a control member positioned for actuation by saidsecond lever, said elements of the magnet couple being held by the forceof magnetic attraction against spring produced separation as long as thespacing between the same is less than a critical distance at which thespring overpowers the forceof magnetic attraction and swings said secondlever and in turn actuates said control member, and a spring operablyconnected with said first-named lever for continuously urging the sameand the feeler roller thereon toward the fixed feeler roller inopposition to the magnetic attraction of the magnet couple and formoving said second lever and the element thereon at least said criticaldistance whenever the spacing between the feeler rollers is less than apredetermined distance.

11. Apparatus as defined in claim 10, comprising a lock-out devicemovable into engagement with one of the levers for preventing movementof the movable feeler roller toward the fixed feeler roller.

12. In a caliper of the character described, an operable control member,a magnet couple consisting of a magnetized element and a companionarmature element magnetically attracted toward one another, one of saidelements being fixed and the other being movable toward and away fromthe fixed element and arranged to engage and operate said controlmember, the movable element being adapted to normally occupy a firstposition close to but spaced from the fixed element in which positionthe force of magnetic attraction between said elements is of increasedintensity and to occupy a second sition spaced farther away from thefixed element in which position said force of magnetic attraction is ofreduced intensity, a spring acting upon the movable element and at alltimes urging the same away from the fixed element, said spring having atension insufficient t verpower th increased force of ma neticattraction with the movable element occupying said normal first positionbut suificient to overpower the reduced force of magneticattraction withthe movable element occupying said second position and move said movableelement from said latter position farther away from the fixed elementand thereby operate said control means, a pair of cooperating feelermembers between which material to be calipered is passed, said feelermembers directly engaging opposite faces of said material, one of saidfeeler members being fixed, the other of said feeler members beingmovable toward and away from the fixed member and engaged with themovable element of the magnet couple whereby movement of said movablefeeler member toward the fixed feeler member beyond a predeterminedposition with respect to said fixed feeler member will impart movementto said movable element from said first position to at least said secondposition, and a spring acting upon the movable feeler member and at alltimes urging the same toward the fixed feeler member, said last-namedspring having a tension sufiicient to move the movable feeler member andthe movable element of the couple.

References Cited in the file of this patent Number magnet couple towardthe fixed feeler member and away 10 2,204,820

from the fixed element, respectively, in opposition to UNITED STATESPATENTS Name Date Shaw Aug. 22, 1939 Pelosi Nov. 14, 1939 Parks June 18,1940

